Role of oxygen-vacancy in piezoelectric properties and fatigue behavior of (Bi0.5Na0.5)0.93Ba0.07Ti1+xO3 ceramics

In this reported study, (Bi0.5Na0.5)(0.93)Ba0.07Ti1+xO3 (abbreviated as BNBT1+x) ceramics, containing Ti-nonstoichiometry that ranged from a 2% deficiency to a 1% excess, were designed and systematically characterized. The results of the X-ray diffraction Rietveld refinement and X-ray photoelectron spectroscopy analysis of these materials revealed that the amount of Ti in the BNBT1+x ceramics significantly affected the degree of coexistent rhombohedral/tetragonal phases and also affected the content of singly/doubly charged oxygen-vacancy (V'(O) /V ''(O)) in the ceramics. After poling and 10(5) fatigue cycles, the variation in Raman resonance line-width of the Ti-O bond in the BNBT1+x ceramics was found to be strongly dependent on the amount of Ti in the ceramic. The Ti-Ti4+((3+)') -V'(O) -> Ti-Ti4+((3+)') -V-O '' transformation and clustering of the defects under electrical loading were considered to be a critical factor in electric field-induced structural transition and fatigue properties of the material.